Two years after she was shot to death near Holly, Michigan, Ally Brueger’s parents and police are still begging for information about the murder of the young nurse, WXYZ reports.

Michigan State Police say they no longer consider Ally’s parents suspects, and her parents say her father has now passed a polygraph test. Originally, police could not rule out either parent largely because they were each other’s alibi: both say they were home together at the time of Ally’s murder.

The 4' 9" dynamo was working at a local hospital and studying for her master's degree in writing.

"Nursing was her profession, but writing was her passion," said Nikki.

Despite her busy life, Ally also found time for another passion: running. She religiously jogged 10 miles a day every day without fail.

"She would run in a blizzard," said Nikki.

And each time she left the house, mom would give Ally the exact same warning: "Be careful out there."

Those were the last words she'd ever speak to Ally as her daughter set out on her usual afternoon run on July 30, 2016.

A local homeowner calls 911: "There's a girl laying in my yard that just got shot a couple of times."

Suddenly, 31-year-old Ally Brueger was fighting for her life after being shot in the back while running one of her regular routes, apparently trying to flee her attacker.

"Laying face down, she's bleeding all over the place. I gotta get out there and see if I can help her," the caller says.

Ally Brueger collapsed probably 50 feet from the dirt road where she was jogging. The man who lives in the house there came out, saw her, ran back in, called 911 and used his hands to plug her wounds to keep her alive until emergency rescue crews got her.

"I was trying to keep her from bleeding to death," the man tells Crime Watch Daily.

The Good Samaritan, who asked that we protect his identity, remembers a critically wounded Ally fading fast as he tended to her.

"Well, then she stopped breathing, and I hollered at her and she started breathing again," the homeowner tells Crime Watch Daily.

But tragically Ally Brueger was officially declared dead on arrival at a local hospital. For her devastated parents it's like time had stopped. Nikki and Franz can't fathom what kind of monster would rob them of their precious only child.

"The circumstances surrounding her murder are unrelenting to me, to Franz," said Nikki.

Local and state police scoured the crime scene and surrounding neighborhood for any clues, witnesses and evidence they could find. And they can tell almost immediately that Ally had been shot from behind with a shotgun.

"We believe five shots were fired," said Michigan State Police Lt. Michael Shaw.

Only one of those shots found its target.

"It hits her in the small part of her back and just happens to hit the wrong blood vessel and she bleeds out," said Lt. Shaw.

Several residents tell police they heard the gunshots, and some say they noticed a white sedan in the area around the time of the murder.

"We had some tire tracks that we believe may have belonged to a vehicle that we thought was out there," said Lt. Shaw.

But apart from that, investigators don't have much to go on. The location of the shooting is problematic in the investigation: dirt road, houses spread far apart, no surveillance cameras and no eyewitnesses.

"There just wasn't that stuff out there," said Lt. Shaw.

And they can only speculate about who might have killed Ally, and why.

"There's so many different scenarios that are possible in this," said Shaw.

One of them is that Ally may have been the victim of a deadly case of road rage.

"Somebody drives by and for whatever reason, they get into it, and she's killed," said Shaw.

Or, unthinkably, that Ally had been deliberately marked for assassination.

"She knew who it was. Somebody that got mad at her at work, something to that effect," said Shaw.

As investigators searched for a suspect, they soon realized she wasn't the only jogger murdered that week.

The murder of 31-year-old Ally Brueger has police baffled, literally left without a clue.

But then, just three days after Ally's killing on July 30, 2016, investigators get an unexpected lead when another young woman is murdered in eerily similar circumstances 600 miles away.

Karina Vetrano was found beaten and strangled to death on a remote trail where she'd gone jogging near her home in Queens, New York.

And just five days after that, a third female jogger, Vanessa Marcotte, was found burned to death in Princeton, Massachusetts.

Those deaths lead police to believe there may be a roaming serial killer on the loose.

"Traveling around and doing it in different places," said Lt. Shaw.

And it only makes Ally Brueger's murder even more horrifying.

"Ally was first. Ally's murder was the first one," said Nikki Brueger.

But the serial killer theory ultimately falls apart when the East Coast murders are found to be unrelated, and police make arrests in each case.

"Everybody was ready to put them together. But just didn't pan out, this as being our person," said Lt. Shaw.

Now Michigan State Police are back to square one and following their initial hunch.

"That she had to know who her killer was. It was just too weird," said Lt. Shaw.

And anyone who knew Ally Brueger is considered a suspect.

"Everyone is in the game," said Lt. Shaw.

Including Wes Sutherland, an ex-boyfriend Ally had lived with for nearly two years before they broke up three months before her murder. Sutherland also worked as an aide at the same hospital as Ally while studying to be a nurse like her, and he had reportedly remained friendly with Ally after the split.

"So being that this is an open investigation, he's a suspect," said Lt. Shaw.

Police had grown suspicious of Wes Sutherland from the first time they interviewed him, believing he was lying and withholding information.

"We know that sometimes he's not absolutely truthful, but maybe he's not absolutely truthful with everybody, not just us," said Lt. Shaw.

And speaking out for the first time in an exclusive interview with Crime Watch Daily, Wes Sutherland admits he did fail one of two police polygraph tests.

"They said that the first one was inconclusive, and then they said that I failed the second one," said Sutherland.

And they specifically asked you, Did you kill Ally?

"Yes," said Sutherland.

How do you explain the fact that you failed the polygraph test when you were asked Did you kill Ally?

"I don't believe I failed. I believe that it was an intimidation tactic," said Sutherland.

Police had also been unable to verify Sutherland's alibi.

Where were you at the precise time of the shooting?

"I was at home," said Sutherland. "Ally and I had actually worked the night before. And she was planning on coming over that morning."

But could they have had one fatal final argument?

And why did you break up?

"Right off the bat was marriage. She wanted to get married immediately," said Sutherland.

And you were not keen on that?

"I was not. I didn't feel like it was responsible to get married until I graduated from college. I wanted to be able to support her," said Sutherland.

But Ally's parents had told a different story.

They say the reason you and Ally broke up was because she found out you are on a dating site.

"That is not the reason we broke up," said Sutherland.

Were you on the dating site?

"I was on a dating site, yes," said Sutherland.

Even though you were seeing Ally?

"We had grown apart because of the marriage thing. The marriage thing was a huge issue," said Sutherland.

Wes Sutherland says they'd reconciled just before Ally Brueger was murdered, and were planning to live together again.

"If anything, the breakup made us realize that we needed each other more than we realized," said Sutherland. "We had come to an agreement that we would get engaged that Christmas, but we won't get married until after I graduated from college. That was the compromise."

And he says he was devastated by the murder of the woman he claims was his fiancée.

"I loved Ally. No question about it," said Sutherland. "Anybody who knows me knows that I loved Ally, and knows the pain that I went through."

Wes Sutherland says it's also painful living under a dark shadow of suspicion.

"It hurts to love someone as much as I loved Ally and to have people look at you that way is extremely painful," said Sutherland.

Sutherland tells Crime Watch Daily just what he told police when they asked him this same question:

Did you kill Ally?

"Absolutely not," said Sutherland.

Were you there when she was shot?

"No," said Sutherland.

And he points the finger at several other possible suspects, including one of Ally's male co-workers and, shockingly, her own parents Nikki and Franz.

I talked to them. They don't seem like the kind of folks who would be capable of killing their one and only daughter.

"Right. I understand that. I can understand that," said Sutherland.

Do you agree with me?

"No," said Sutherland.

You think that her parents were capable of killing her?

"I think that her father could be, yeah," said Sutherland. "The relationship that she had with her father was not good."

Wes Sutherland also quotes Ally's mom Nikki as telling him that her husband gets angry with her for continuing to mourn their daughter's death.

"She said that she's been having a rough time with Franz, her father, that they had recently gotten into an argument because Franz had told her that she should just get over it," said Sutherland.

But that doesn't make him a killer.

"It does not make him a killer. It's an odd thing for a loving father to be saying a few months after his daughter was murdered," said Sutherland.

Franz Brueger scoffs at Wes Sutherland's stunning accusation, but doesn't care to get in a finger-pointing match with him.

"I'm not that easy to judge people, you know. I just wait and see," said Franz Brueger.

Wife Nikki is not so forgiving of Wes Sutherland.

"I won't have anything to do with him. I won't talk to him," Nikki said.

Perhaps just as surprising as Sutherland's accusation against Ally's parents is the reaction of the police to it.

"We have not ruled out anyone. Including mom and dad," said Lt. Shaw.

Nor Wes Sutherland.

"He's not been ruled out," said Shaw.

Police also say that failing a polygraph test doesn't mean Wes Sutherland had anything to do with Ally Brueger's murder.

"It wouldn't be fair for us to say that just because he lied to us, you know, that he's a killer," said Lt. Shaw. "People lie to us all the time. Does that make you a murderer? It doesn't."

And more than 18 months after Ally was killed, police remain confident they will eventually catch whoever did it.

"There's one tiny piece of the puzzle that we're looking for. That we either need the person that was involved to tell us about, or the person that was told. And once they do that, we will solve this case," said Shaw.

Ally's grieving mom says she won't rest until they do.

"Just because she's not here in the flesh doesn't mean she's not here in the spirit," said Nikki. "I'll always be her mother. That's my responsibility as her mother to find out what happened to her."

Anyone with information leading to the arrest of the person or people responsible for the murder of Ally Brueger is asked to contact Michigan State Police at (855) MICH-TIP. There is a reward of up to $13,500.